Orange County, once a GOP stronghold, has faded from red to pink with the emergence of Latino voters, who are repelled by the party's stand on immigration.

A northwestern chunk of Orange County fell to the Democrats when GOP Assemblyman… (Marc Martin / Los Angeles…)

Orange County was once an instant synonym for Republican power, and the GOP's dominance looked impregnable. Now, battered by the recent election results and dismayed by the slow, steady decline in party registration, Republicans here are struggling to craft a new strategy.

The percentage of registered Republicans has eroded — it now stands at 41% — and the party has long since lost control of the political districts that envelop the county seat of Santa Ana, a Latino-dominated city of 330,000, and surrounding communities in the county's core.

This month's election brought more blows. For the second time, the once-red city of Irvine voted for Barack Obama over the Republican candidate. And a northwestern chunk of the county fell to the Democrats when GOP Assemblyman Chris Norby, an outspoken conservative, lost to Latina schoolteacher Sharon Quirk-Silva.

Asked to explain the loss, Scott Baugh, chairman of the county's Republican Party, attributed it to "not fully appreciating the demographic shift and not seeing it in time."

Baugh and other Republicans say Latinos belong naturally in the GOP, citing a cultural emphasis on faith, family, education and the value of hard work.

If Congress deals with the immigration issue, "It's game on again in terms of a competition of ideas and values," Baugh said. "You could wipe out a decade of declining registration by demonstrating to the Latino community that the values they have are the values we have."

Right now, with the immigration issue near the top of Latinos' concerns, many Republicans say their core message of liberty, family values and a free market falls on deaf ears.

"The Republican Party has done such a poor job of, one, messaging; and two, letting themselves be demonized and not fighting back," said Teresa Hernandez, who runs the immigration reform committee for the Lincoln Club of Orange County, a conservative group. "If I knock on the door and say, 'I'm a Republican,' they don't want to hear what I say on the economy or education because they have it in their mind that I'm a bigot."

To appreciate the scale of the countywide political shift, consider that in mid-1996, when registered Republicans eclipsed Democrats 52% to 32%, no Orange County Democrat held a single partisan elected office on the county, state or federal level.

This is the county that yielded conservative firebrands Robert K. Dornan and Wally George, and has long been associated publicly with right-of-center social causes, as in the late 1970s, when a state senator from Fullerton launched a ballot measure to bar gay teachers from California schools.

By a recent count, about 34% of the county's roughly 3 million people are Latino — a powerful voting bloc with strong Democratic leanings. In the presidential election, President Obama won 71% of the Latino vote nationwide to Mitt Romney's 27%.

For the Orange County GOP, the effort to capture the Latino vote has proved elusive, in no small part because the county has a reputation as a cradle of border-crackdown activism, such as Proposition 187, the 1994 initiative intended to cut public services for illegal immigrants.

When President George W. Bush came to Irvine in 2006 to pitch his immigration reform plan — which involved a guest-worker program — some local notables in his own party refused to attend, criticizing his plan as amnesty for illegal immigrants. Dana Rohrabacher, the longtime Republican congressman from Huntington Beach, noted that a photo op with the president would be politically imprudent in such a setting.

Irvine offers a window into the GOP's struggles.

Joseph Cruz, an Irvine tax attorney and second-generation Filipino American, went to the polls feeling no hesitancy about which party to vote for. A path to citizenship for America's undocumented population was a top priority, which he said aligned him with Democrats.

"People assume it's a Latino thing," Cruz said of immigration reform, but as an Asian American, he feels estranged from Republicans who "haven't said anything that's really solution-based."

Cruz, 36, reflects the changing face of Irvine, Orange County's third-largest city and its emblematically master-planned centerpiece, where the Asian population has shot from 8% in 1980 to nearly 40% now.